[Dip] "Not a mixed-integer problem" message when using DIP with CPLEX

[Matthew Galati]

I've seen this for a while and well after the fixes mentioned. It has no
real effect on DIP as far as I can tell. But, I'll investigate when I have
time.



On Wed, Jan 26, 2011 at 3:18 PM, Ted Ralphs <ted at lehigh.edu> wrote:

> We've seen messages like this with CPLEX for a long time in many
> contexts (not just DIP). Unlike most other solvers, CPLEX makes a very
> strong distinction between an LP and a MIP. Although conceptually, the
> only difference is whether there exist variables that are marked as
> integer type or not, CPLEX takes the "problem type," as set by the
> user, as strongly dictating what can and cannot be done when
> manipulating the model. CPLEX also erases all solution information
> when switching problem type. The use of Cgl actually requires the
> problem type to be switched back and forth and this causes problems. I
> thought we had actually fixed all of these problems over time, so if
> you are seeing this error now, it should be an indication of a true
> problem.
>
> Ted
>
> On Wed, Jan 26, 2011 at 1:49 PM, Matthew Galati
> <matthew.galati at gmail.com> wrote:
> > I know about it.... it doesn't seem to effect anything - except that it
> is
> > annoying.
> >
> > It is on my ToDo list to investigate why that message appears. I think it
> > has something to do with the odd design of OsiCpx.
> >
> >
> >
> > On Wed, Jan 26, 2011 at 1:46 PM, kim <kim at hamilton-vejlin.dk> wrote:
> >>
> >> I just set up DIP to use CPLEX instead of CBC and it works well but I am
> >> getting some odd messages at the beginning of the program run.
> >>
> >> As one of the first things I get a string of messages all saying:
> >> "CPX0000  CPLEX Error  3003: Not a mixed-integer problem."
> >>
> >> This happens before the search is actually started and there is always
> >> one "error 3003" for each block. It doesn't seem to have an effect at
> >> all and the program behaves as expected, but it seems odd.
> >>
> >> Does anyone have in idea what those messages are about and if I should
> >> see it as a sign I have not set up the DIP/CPLEX combination correctly?
> >>
> >> -Kim
> >>
> >> _______________________________________________
> >> Dip mailing list
> >> Dip at list.coin-or.org
> >> http://list.coin-or.org/mailman/listinfo/dip
> >
> >
> > _______________________________________________
> > Dip mailing list
> > Dip at list.coin-or.org
> > http://list.coin-or.org/mailman/listinfo/dip
> >
>
>
>
> --
> Dr. Ted Ralphs
> Associate Professor, Lehigh University
> (610) 628-1280
> ted 'at' lehigh 'dot' edu
> coral.ie.lehigh.edu/~ted
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://list.coin-or.org/pipermail/dip/attachments/20110126/f415e8ed/attachment.html